There is known a walking assistance device for assisting a person with impaired motor function of the lower limbs, caused by lesion or advanced age, in walking, comprising a pelvis support member adapted to be worn on a pelvis of a wearer, a thigh support member adapted to be worn on a thigh of the wearer, a leg support member adapted to be worn around a leg of the wearer, a knee joint hinge disposed at a position corresponding to a side part of a knee of the wearer and connecting the leg support member to the thigh support member in a manner that enables back-and-forth rotation of the leg support member with respect to the thigh support member, a hip joint electric motor disposed at a position corresponding to a side part of a hip joint of the wearer for providing the thigh support member with an assisting force to assist the movement of the thigh, and a knee joint electric motor mounted to the knee joint hinge for providing the leg support member with an assisting force to assist the movement of the leg (see, for example, Japanese patent laid open publication No. 2006-75226).
The above-mentioned walking assistance device has 4 electric motors, each two of which are placed on either side of the device, and thus is capable of assisting the movement of the thighs using the output of the hip joint electric motors and the movement of the legs using the output of the knee joint electric motors.
In the above-mentioned walking assistance device, as the knee joint electric motor is disposed on the knee joint, the hip joint electric motor rotates the thigh support member along with the knee joint electric motor, and thus the load on the hip joint electric motor increases, thereby increasing its power consumption. In addition, if the electric motor, which is a heavy load, is disposed on the knee joint whose movement range is broad, the inertia mass of the knee of the wearer increases, thereby hampering the natural walking sense and disrupting the walking pace of the wearer.